Modeling modified Circumpolar Deep Water intrusions onto the Prydz Bay continental shelf, East Antarctica

• Published in: Journal of geophysical research. Oceans Vol. 122; no. 7; pp. 5198 - 5217
• Main Authors: Liu, Chengyan, Wang, Zhaomin, Cheng, Chen, Xia, Ruibin, Li, Bingrui, Xie, Zelin
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-07-2017
• Subjects: Amery Ice Shelf; Boreholes; Circumpolar Deep Water; Coastal currents; Coastal environments; Continental shelves; Deep water; Evaluation; Geophysics; Heat; Heat transport; Ice calving; Ice front; Ice fronts; Ice shelves; Identification; Induction heating; intrusion path; Land ice; Modelling; modified Circumpolar Deep Water; Prydz Bay; Satellites; Sea ice; Seasonal variation; Slope currents; Submarine troughs; Transport; Troughs
• DOI: 10.1002/2016JC012336
• EISSN: 2169-9291
• ISSN: 2169-9275

An eddy‐resolving coupled regional ocean‐sea ice‐ice shelf model is employed to locate the hot spots where modified Circumpolar Deep Water (mCDW) intrudes onto the continental shelf within Prydz Bay, and locate the paths through which mCDW is transported to the Amery Ice Shelf (AIS) calving front. Evaluation of the model output is with satellite, hydrographic and borehole data. Two critical windows responsible for mCDW intrusions are identified. The first is the eastern branch of the cyclonic Prydz Bay gyre (PBG) that carries mCDW to the ice front line, accounting for an annual mean heat transport of ∼8.7 ×1011 J s−1. The second is located to the east of the Four Ladies Bank (FLB) where mCDW is channeled through submarine troughs, accounting for an annual mean heat transport of ∼16.2 ×1011 J s−1. The eddy‐induced heat transport accounts for ∼23% in the path of the PBG and ∼52% in the path of the eastern coastal current, with respect to their total onshore heat transport. The seasonal pulsing of mCDW intrusions is greatly dependent on the seasonal cycle of the Antarctic Slope Current (ASC) that peaks with a maximum of ∼29.3 Sv at 75°E in June. In austral winter, mCDW is allowed to access the eastern flank of the AIS calving front with potential consequences for the basal mass balance of the AIS. The dynamic effects of small‐scale troughs on the longshore ASC play an important role in the onshore mCDW transport.
Key Points
Two critical regions responsible for modified Circumpolar Deep Water intrusions are identified in Prydz Bay
Both the eastern coastal current and the Prydz Bay gyre serve to transport modified Circumpolar Deep Water to the ice calving front
The need to reproduce dynamic effects of small‐scale troughs on the Antarctic Slope Current is highlighted